This invention relates generally to metronomes of the type having a clock work escapement which oscillates the pendulum. More particularly, the invention relates to precision metronomes having provision for minimizing or eliminating limp, or unequal back-and-forth reciprocation of the pendulum.
A prior device of the above type is disclosed and claimed in U.S. Pat. No. 3,486,323 dated Dec. 30, 1969, and issued to Frederick Franz. The device shown therein included a metronome having a yieldable two-layer spring drive between a reciprocating (driven) shaft and a pendulum. By virtue of the spring arrangement, there was minimized the possibility that forcible movement of the pendulum would inadvertently result in damage to the teeth of the escapement wheel after the metronome had run down. As shown, the metronome movement was suspended from the housing or base by means of a pair of bearing arms which were disposed on a horizontal shaft. With such an arrangement, if the housing was placed on a sloping surface (non-horizontal), the metronome movement was capable of automatic arcuate accommodation or adjustment such that it remained in a generally vertical plane at all times.
While the above patented device operated in a very satisfactory manner, it was found to be inconvenient to adjust the movement at the factory so as to reduce limp which arose from slight misalignments due to tolerances of the various components, including those of the escapement wheel and pallets. Limp resulting from such misalignments is difficult to predict, and accordingly is difficult to compensate for. Also, in the patented device the double-layer spring drive connection was found to entail an unnecessarily high cost for the coil spring component.